Grab bucket



Aug. 24, 1965 Filed July 31, 1963 J. BIENAIME GRAB BUCKET 3 Sheets-Sheeti /N VENTOF? JACQUES BIENAIME Aug. 24, 1965 Filed July 31, 1963 J. BIENAIME 3,202,306

GRAB BUCKET 3 Sheets-Sheet 2 INVENTOF? JACQUES BIENAIMEZ Aug. 24, 1965 J. BIENAIME 3,202,305

GRAB BUCKET Filed July 51, 1965 5 Sheets-Sheet 3 INVENTOR dncpws BMNJ/M' United States Patent M 3,202,306 GRAB BUCKET Jacques Bienaime, Paris, France, assignor to Yumho,

Genas, Isere, France, a body corporate of France Filed July 31, 1963, Ser. No. 298,850

(Ilaims priority, appiication France, Aug. 28, N62, 908,02il '7 Claims. (Cl. 214-456} This invention relates in general to grab buckets or clamshells and has specific reference to a grab bucket of the type comprising a pair of pivotally mounted opposed shells operated by a fiuid-actuated motor comprising a fixed body acting as a piston and supporting said shells, and a movable assembly connected to said shells. Grab buckets of this general type are a standard equipment in handling or loading machines, hoisting apparatus, cranes, excavators, etc.

Grab buckets of the type broadly set forth hereinabove are already known wherein the shells are carried by a rudder-bar or like rocking-lever pivotally mounted on the lower portion of a piston having its rod solid with the boom of the handling or like machine. Slidably mounted on this piston is the movable assembly of the fluid-actuated motor which is connected through adequate linkage means to said shells.

These known grab buckets are characterized by various drawbacks, due notably to the mounting of the shellsupporting rocker-arm on the lower portion of the piston, whereby the latter must compulsorily extend through the movable assembly at its two ends. The manufacture of the fluid-actuated motor is complicated by this mounting, more particularly in that sealing devices must be provided at both ends of the movable assembly. On the other hand, the necessity of extending the piston or providing a rod constituting the piston extension leads to the suppression or at least the reduction of one of the useful surface areas thereof.

On the other hand, these grab buckets are objected to on account of their rotary mounting in relation to the fixed element of the operating motor. In fact these grabs are liable, during the shell operation, to rotate unduly and therefore to interfere with the loading and unloading operations. 7

Finally, the efforts applied on the shells by the materials being handled, which are transmitted throughout the aforesaid movable assembly slidably mounted on the fixed body as explained hereinabove, involve a deformation and a relatively fast wear or" the motor.

Inview of the foregoing, it is the essential object of the present invention to provide'a grab bucket free of the drawbacks listed hereinabove and which is remarkable notably in that the shells are pivotally mounted on a frame rigid with the rod of the fixed piston and wherein said movable assembly is slidably mounted.

Under these conditions, the grab bucket can be secured on the piston rod instead of on an extension of this piston which extends through the movable assembly, whereby the motorconstruction is greatly simplified. on the other hand, the hydraulic pressure is exerted on the entire cross-sectional' area of the piston, thus increasing the efliciency of the motor.

According to a further feature characterizing this invention the aforesaid frame is rotatably mounted on the piston rod and has its axis of rotation coincident with the piston rod axis.

3 ,282,366 Patented Aug. 24, 1965 It is a complementary feature of this invention to provide locking means for providing the rotation of said frame about the piston rod when the hydraulic circuit is under pressure.

Therefore, the assembly of this invention permits the desired angular setting of the grab bucket about its vertical axis while preventing any untimely rotational movement thereabout during the loading and unloading operations.

Still in accordance with this invention, the movable assembly is provided with guide means 'co-operating with said frame.

These guide means are designed with a view to improve the resistance of said movable assembly to the stress transmitted thereto by said shells.

This invention is also concerned, by way of novel industrial products with the earth-moving machines, vehicles and means, as well as handling and hoisting machines, whenever they are equipped with grab buckets of the aforesaid type.

Reference will now be made to the accompanying drawings illustrating diagrammatically by way of example a typical form of embodiment of the invention.

In the drawings:

FIGURE 1 is a side elevational view of the device of this invention;

FIGURE 2 is a side elevational view of the same device with parts broken away; and

7 FIGURE 3 illustrates on a larger scale means for locking said frame against rotation in relation tothe piston rod.

Referring first to FIGURES 1 and 2 of the drawings it will be seen that the device according to this invention comprises essentially a frame structure'l consisting of two vertical parallel uprights 2a, 2b interconnected at their upper ends by a cross member or like element 3. This frame supports at its lower end the shells 4a, 4b pivoted on pins 5a, 5b.

The device also comprises a fluid-actuated motor 6 consisting of a movable assembly 7 and a fixed piston 8 having its rod 9 secured directly on a strap or like member 10 rigid with the boom or like element 11 of the machine.

Two ducts 12, 13 are provided for supplying hydraulic fluid under pressure to said movable assembly, these ducts opening respectively on the front face of piston 8 and in the vicinity of its rear face in order to provide a double-acting motor.

The movable assembly 7 is connected to the clamshells through links 14a, 14b articulated respectively at Ma, 14"42, and 1412, 14"b, and provided with guide rollers 15a, 1512 (which are four in number in the example illustrated) rolling on ribs 16a, 16b formed along the frame 1. i

The cross member 3 of frame 1, as shown in FIG. 3, comprises a lowerannular member 3a having a relatively large internal diameter, said member 3a being secured, for example by soldering, to the upper extremities of up rights 2a, 2b and and upper annular member 312 having an internal diameter slightly larger than the external diameter of rod 9, said member 3b being secured, for example by soldering, to memberSa is fitted between two friction discs 17a, 17b, for example of bronze or any other suitable alloy, constituting locking means preventing, as will be explained presently, the rotation of the frame when the hydraulic circuit is under pressure. The disc 17a bears against a flange or like annular projection 18 of the rod. The two friction discs 17a, 17b and cross member 3 are adapted to be adjustably clamped together by means of a tightening nut 19 screwed on rod 9 and provided with a lock member 20. This member bears against the disc 1712 by means of a lock washer 21 slipped on the piston rod. Thus, by more or less tightening of the nut 19 the torque resulting from the rotational resistance of the joint may be adjusted to a predetermined limit.

Accordingly as the hydraulic fluid is directed into one or the other ducts 12 or $13, the movable assembly '7 is slidably moved upwards or downwards on the frame 1 and through the links 14a, 14b causes the shells 4a and 4b to pivot about their relevant pins 5a, 5b.

When one of the hydraulic circuits is connected through a control valve or other suitable means with the source of fluid under pressure, the motor eiiorts are transmitted through said links and shells to the frame, these efforts being directed vertically upwards or downwards according to the direction of motion of the sliding movable assembly. Assuming that the movable assembly is in the lower position shown in FIG. 1 and moves upwardly, a force F is applied to each one of the shells 4a, 4b at 14"a and 14"b respectively; each force F has a resultant force F in the direction =14"a5a l=4"b-5b respectively. Each force F applied at 5a and 5b has a resultant torce P" which urges frame structure 1 upwardly. For the purpose of clarity only one of the two forces F" has been illustrated in FIG. 1. This force F" tends to lift the frame structure 1 and consequently its cross member 3 and effect a relatively small upward displacement of the latter on piston rod 9 which is fixedly secured on boom Id at It) and cannot move, which is opposed by resilient friction disc 17b, thus effectively locking the frame structure and its cross member 3 as well as the grabs supported by said frame structure against rotation about the axis of piston rod 9. It will be understood that the motion of the movable assembly in the opposite direction will cause a reversal in the direction of F. This will elfect'a relatively small downward displacement of the cross member 3 on fixed piston rod 9 which will be opposed by friction disc 17a, thus again effectively locking the frame structure 1712 and its cross member 3 as well as the grabs supported by said frame structure about the axis of piston rod 9. As a result, whatever the direction in which these efforts are exerted, the cross member 3 of the frame is pressed against one of the friction discs 17a or 17b acting as locking member and preventing the rotation of the grab bucket about its vertical axis. Therefore, this mounting constitutes a self-locking system whereby the bucket or clamshell can be set in the desired direction as a function of the desired operation or type of work, and to maintain this angular setting throughout the .bucket operation in spite of rotational efforts applied to the bucket as a consequence either of its inherent inertia or of the resistance exerted by the material being handled against the shells.

On the other hand, it will be noted that efforts resulting from the various stresses exerted on the grab, notably those caused by the resistance exerted by the material being handling on the shells, are absorbed "by the rollers 15a, 15b.

Of course, many modifications and variations may be brought to the form of embodiment shown and described herein, without however departing from the spirit and scope of the invention as set forth in the appended claims.

Thus, simple shoes or like members sliding on slideways or the like may be substituted for the friction rings illustrated in this example. I

Of course, the invention should not be construed as being limited by the specific form of embodiment thereof which is'shown and described herein, as many modifica- 4. tions may be brought thereto without departing from the basic principles set forth hereinabove.

What I claim is:

1. A grab bucket comprising a fluid motor structure having a substantially vertical fixed rod-piston means and a cylinder shaped sliding movable assembly, said rodpiston means comprising a piston having a lower face and an upper face and a rod protruding upwardly from said upper face, means at the upper end of said rod for suspending the latter, said rod-piston means also including fluid supply duct means opening on said lower face and in the vicinity of said upper face respectively, said cylinder shaped sliding movable assembly having an upper end provided with an axial opening for the passage of said rod and a closed lower end, a frame structure rotatably mounted on said rod in the vicinity of the upper end thereof, the axis of rotation of said frame structure being coincident with the axis of the rod, said frame structure and said sliding movable assembly both including guide means adapted to cooperate with each other during the motion of said sliding movable assembly, shells articulated on said frame structure, and link means pivotally connected with said sliding movable assembly and with said shells whereby the motion of said sliding movable assembly causes the opening and closing of said shells.

2. A grab bucket as claimed in claim 1 wherein said frame structure comprise-s vertical parallel uprights interconnected at their upper ends to a cross member adapted to he slipped on said rod.

3. A grab bucket .as claimed in claim 1 wherein said guide means comprise slideways formed along said frame structure and rollers mounted on said sliding movable assembly.

'4. A grab bucket as claimed in claim 3 including a cross member for said frame structure adapted to be slipped on said rod .and wherein said rod includes an annular projection located in the vicinity of its end, said .annular projection forming an abutment for said cross member.

5. A grab bucket for an excavator including a boom and a strap secured to said boom, said grab bucket comprising a fiui-d motor structure having a fixed rod-piston means and a cylinder-shaped sliding movable assembly, said rod-piston means having a piston having a front face and a rear face and a rod protruding from said rear face, said rod having its end pivoted on said strap, said rodpiston means also including fluid supply duct means opening on said front face and in the vicinity of said rear face respectively, a frame structure rotatably mounted on said rod, its axis of rotation being coincident with the axis of the rod, said frame structure and said sliding movable assembly both including guide means adapted to cooperate with each other during the motion of said sliding movable assembly, shells articulated on said frame structure, link means pivotally connected with said sliding movable assembly and with said shells whereby the motion of said sliding movable assembly causes the opening and closing of said shells, said frame structure comprising vertical parallel uprights, and a cross member interconnecting the upper ends of said uprights adapted to be slipped on said rod, said guide means comprising slideways formed along said uprights and rollers mounted on said slidable movable assembly, said rod including an annular projection located in the vicinity of its end, said annular projection providing an abutment for said crossmember and locking means on said rod and said frame structure, said loclsing means being brought into operation by the movement of said sliding'movable assembly for locking said frame structure against rotation.

6. A grab bucket as claimed in claim 5 wherein said locking means includes a lower friction disc between said annular projection and said cross member, a washer sl pped on said rod above said cross member, on upper r ction disc between said cross member and said washer, ad ustment means bearing on said washer for adjusting the pressure deve-ioped between said fmiction discs and said cross member.

"7. A grab buoket as claimed in claim 6 wherein said adjustment means consist of a tightening nut screwed on said rod and provided with a l ock nut.

References Cited by the Examiner UNITED STATES PATENTS 6 Przybylski 214-6 57 X Ives.

:Chartrenet 2J14-658 X Crampton. Redman 214-656 He-din 214656 HUGO O. SOHULZ, Primary Examiner.

8/17 Fogiarity 214-656 X 10 MORRIS TEMIN, Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,202,306 August 24, 1965 Jacques Bienaime It is hereby certified that error appears in the above numbered pat- :nt requiring correction and that the said Letters Patent should read as :orrected below.

Column 2, line 2, for "providing" read preventing line 60, for "and", second occurrence, read an column 3", line 63, for "handling" read handled Signed and sealed this 8th day of March 1966.

{NEST w. SWIDER EDWARD -J. BRENNER testing Officer Commissioner of Patents 

1. A GRAB BUCKET COMPRISING A FLUID MOTOR STRUCTURE HAVING A SUBSTANTIALLY VERTICAL FIXED ROD-PISTON MEANS AND A CYLINDER SHAPED SLIDING MOVABLE ASSEMBLY, SAID RODPISTON MEANS COMPRISING A PISTON HAVING A LOWER FACE AND AN UPPER FACE AND A ROD PROTRUDING UPWARDLY FROM SAID UPPER FACE, MEANS AT THE UPPER END OF SAID ROD FOR SUSPENDING THE LATTER, SAID ROD-PISTON MEANS ALSO INCLUDING FLUID SUPPLY DUCT MEANS OPENING ON SAID LOWER FACE AND IN THE VICINITY OF SAID UPPER FACE RESPECTIVELY, SAID CYLINDER SHAPED SLIDING MOVABLE ASSEMBLY HAVING AN UPPER END PROVIDED WITH AN AXIAL OPENING FOR THE PASSAGE OF SAID ROD AND A CLOSED LOWER END, A FRAME STRUCTURE ROTATABLY MOUNTEDON SAID ROD IN THE VICNITY OF THE UPPER END THEREOF, THEAXIS OF ROTATION OF SAID FRAME STRUCTURE BEING COINCIDENT WITH THE AXIS OF THE ROD, SAID FRAME STRUCTURE AND SAID SLIDING MOVABLE ASSEMBLY BOTH INCLUDING GUIDE MEANS ADAPTED TO COOPERATE WITH EACH OTHER DURING THE MOTION OF SAID SLIDING MOVABLE ASSEMBLY, SHELLS ARTICULATED ON SAID FRAME STRUCTURE, AND LINK MEANS PIVOTALLY CONNECTED WITH SAID SLIDING MOVABLE ASSEMLBY AND WITH SAID SHELLS WHEREBY THE MOTION OF SAID SLIDING MOVABLE ASSEMBLY CAUSES THE OPENING AND CLOSING OF SAID SHELLS. 